JEE MAIN - Chemistry (2025 - 8th April Evening Shift)

1
The atomic number of the element from the following with lowest 1st ionisation enthalpy is :
Answer
(D)
87
2

Match the LIST-I with LIST-II

LIST-I
(Complex/ Species)
LIST-II
(Shape & magnetic moment)
A. [Ni(CO)4]I. Tetrahedral, 2.8 BM
B. [Ni(CN)4]2–II. Square planar, 0 BM
C. [NiCl4]2–III. Tetrahedral, 0 BM
D. [MnBr4]2–IV. Tetrahedral, 5.9 BM

Choose the correct answer from the options given below:

Answer
(C)
A-III, B-II, C-I, D-IV
3

Match the LIST-I with LIST-II

LIST-I LIST-II
A. Carbocation I. Species that can supply a pair of electrons.
B. C-Free radical II. Species that can receive a pair of electrons.
C. Nucleophile III. sp2 hybridized carbon with empty p-orbital.
D. Electrophile IV. sp2/sp3 hybridized carbon with one unpaired electron.

Choose the correct answer from the options given below:

Answer
(C)
A-III, B-IV, C-I, D-II
4
In a first order decomposition reaction, the time taken for the decomposition of reactant to one fourth and one eighth of its initial concentration are $t_1$ and $t_2$ (s), respectively. The ratio $t_1/t_2$ will be:
Answer
(D)
$\frac{2}{3}$
5

Correct statements for an element with atomic number 9 are:

A. There can be 5 electrons for which $m_s = +\frac{1}{2}$ and 4 electrons for which $m_s = -\frac{1}{2}$.

B. There is only one electron in $p_z$ orbital.

C. The last electron goes to orbital with $n = 2$ and $l = 1$.

D. The sum of angular nodes of all the atomic orbitals is 1.

Choose the correct answer from the options given below:

Answer
(C)
A and C Only
6
$\mathrm{HA}(a q) \rightleftharpoons \mathrm{H}^{+}(a q)+\mathrm{A}^{-}(a q)$

The freezing point depression of a 0.1 m aqueous solution of a monobasic weak acid HA is 0.20 °C. The dissociation constant for the acid is

Given: $K_f$(H2O) = 1.8 K kg mol−1, molality ≡ molarity

Answer
(B)
$1.38 \times 10^{-3}$
7

What is the correct IUPAC name of the compound?

JEE Main 2025 (Online) 8th April Evening Shift Chemistry - Basics of Organic Chemistry Question 15 English
Answer
(B)
4-Ethylcyclopent-2-en-1-ol
8

JEE Main 2025 (Online) 8th April Evening Shift Chemistry - Haloalkanes and Haloarenes Question 7 English

'P' is

Answer
(C)
JEE Main 2025 (Online) 8th April Evening Shift Chemistry - Haloalkanes and Haloarenes Question 7 English Option 3
9
On combustion 0.210 g of an organic compound containing C, H and O gave 0.127 g H2O and 0.307 g CO2. The percentages of hydrogen and oxygen in the given organic compound respectively are:
Answer
(B)
6.72, 53.41
10

The number of species from the following that are involved in sp3d2 hybridization is :

[Co(NH3)6]3+, SF6, [CrF6]3−, [CoF6]3−, [Mn(CN)6]3−, and [MnCl6]3−

Answer
(B)
3
11
Which of the following binary mixture does not show the behaviour of minimum boiling azeotropes?
Answer
(B)
$\text{C}_6\text{H}_5\text{OH} + \text{C}_6\text{H}_5\text{NH}_2$
12

Given below are two statements:

Statement I: H2Se is more acidic than H2Te

Statement II: H2Se has higher bond enthalpy for dissociation than H2Te

In the light of the above statements, choose the correct answer from the options given below:

Answer
(D)
Statement I is false but Statement II is true
13

$\mathrm{A} \xrightarrow[\text { (i) } \mathrm{H}_3 \mathrm{O}^{+}]{\text {(i) } \mathrm{NaH}} \mathrm{B} \xrightarrow[\text { (ii) } \mathrm{H}_2 \mathrm{SO}_4, \Delta]{\text { (i) } \mathrm{EOH}} \mathrm{C}$

' A ' shows positive Lassaign's test for N and its molar mass is 121 .

' B ' gives effervescence with aq $\mathrm{NaHCO}_3$.

'C' gives fruity smell.

Identify $\mathrm{A}, \mathrm{B}$ and C from the following.

Answer
(C)
JEE Main 2025 (Online) 8th April Evening Shift Chemistry - Compounds Containing Nitrogen Question 9 English Option 3
14
The correct decreasing order of spin only magnetic moment values (BM) of Cu+, Cu2+, Cr2+ and Cr3+ ions is :
Answer
(C)
Cr2+ > Cr3+ > Cu2+ > Cu+
15

Given below are two statements:

Statement I: A homoleptic octahedral complex, formed using monodentate ligands, will not show stereoisomerism.

Statement II: cis- and trans- platin are heteroleptic complexes of Pd.

In the light of the above statements, choose the correct answer from the options given below:

Answer
(A)
Statement I is true but Statement II is false
16
When JEE Main 2025 (Online) 8th April Evening Shift Chemistry - Aldehydes, Ketones and Carboxylic Acids Question 10 English undergoes intramolecular aldol condensation, the major product formed is :
Answer
(B)
JEE Main 2025 (Online) 8th April Evening Shift Chemistry - Aldehydes, Ketones and Carboxylic Acids Question 10 English Option 2
17

Choose the correct set of reagents for the following conversion.

JEE Main 2025 (Online) 8th April Evening Shift Chemistry - Haloalkanes and Haloarenes Question 6 English
Answer
(C)
$\mathrm{Br}_2 / \mathrm{Fe} ; \mathrm{Cl}_2, \Delta$; alc. KOH
18

Which one of the following reactions will not lead to the desired ether formation in major proportion?

(iso- $\mathrm{Bu} \Rightarrow$ isobutyl, sec $-\mathrm{Bu} \Rightarrow$ sec-butyl, $\mathrm{nPr} \Rightarrow \mathrm{n}$-propyl, $$ { }^{\mathrm{t}} \mathrm{Bu} \Rightarrow \text { tert-butyl, } \mathrm{Et} \Rightarrow \text { ethyl) } $$

Answer
(B)
iso- $\mathrm{Bu} \overline{\mathrm{O}} \stackrel{+}{\mathrm{Na}}+\mathrm{sec}-\mathrm{BuBr} \longrightarrow$ sec- $\mathrm{Bu}-\mathrm{O}-$ iso -Bu
19

Match the LIST-I with LIST-II

LIST-I (Reagent)LIST-II (Functional Group detected)
A. Sodium bicarbonate solutionI. double bond/unsaturation
B. Neutral ferric chlorideII. carboxylic acid
C. ceric ammonium nitrateIII. phenolic - OH
D. alkaline KMnO4IV. alcoholic - OH

Choose the correct answer from the options given below:

Answer
(D)
A-II, B-III, C-IV, D-I
20

JEE Main 2025 (Online) 8th April Evening Shift Chemistry - Aldehydes, Ketones and Carboxylic Acids Question 9 English

Choose the correct option for structures of $A$ and $B$, respectively

Answer
(C)
JEE Main 2025 (Online) 8th April Evening Shift Chemistry - Aldehydes, Ketones and Carboxylic Acids Question 9 English Option 3
21

Consider the following half cell reaction

$$ \text{Cr}_2\text{O}_7^{2-} \, (\text{aq}) + 6\text{e}^- + 14\text{H}^+ \, (\text{aq}) \rightarrow 2\text{Cr}^{3+} \, (\text{aq}) + 7\text{H}_2\text{O} \, (\ell) $$

The reaction was conducted with the ratio of $$\frac{[\text{Cr}^{3+}]^2}{[\text{Cr}_2\text{O}_7^{2-}]} = 10^{-6}$$. The pH value at which the EMF of the half cell will become zero is __________.

(nearest integer value)

[Given: standard half cell reduction potential $$E^{\circ}_{\text{Cr}_2\text{O}_7^{2-}, \text{H}^+/\text{Cr}^{3+}} = 1.33\, \text{V}$$, $$\frac{2.303RT}{F} = 0.059\, \text{V}$$.]

Answer
10
22
The energy of an electron in the first Bohr orbit of the H-atom is -13.6 eV.

The magnitude of energy value of an electron in the first excited state of Be3+ is ________ eV (nearest integer value).
Answer
54
23

The equilibrium constant for decomposition of $\text{H}_2\text{O(g)}$

$ \text{H}_2\text{O(g)} \rightleftharpoons \text{H}_2\text{(g)} + \frac{1}{2}\text{O}_2\text{(g)} \quad (\Delta G^\circ = 92.34 \, \text{kJ mol}^{-1}) $

is $8.0 \times 10^{-3}$ at 2300 K and total pressure at equilibrium is 1 bar. Under this condition, the degree of dissociation ($\alpha$) of water is _________ $\times 10^{-2}$ (nearest integer value).

[Assume $\alpha$ is negligible with respect to 1]

Answer
5
24

20 mL of sodium iodide solution gave 4.74 g silver iodide when treated with excess of silver nitrate solution. The molarity of the sodium iodide solution is _______ M. (Nearest Integer value)

(Given : Na = 23, I = 127, Ag = 108, N = 14, O = 16 g mol-1)

Answer
1
25

Resonance in $\mathrm{X}_2 \mathrm{Y}$ can be represented as

JEE Main 2025 (Online) 8th April Evening Shift Chemistry - Thermodynamics Question 13 English

The enthalpy of formation of $X_2Y$ $ \left(X = X(g) + \frac{1}{2} Y = Y(g) \rightarrow X_2Y(g) \right) $ is 80 kJ mol$^{-1}$. The magnitude of resonance energy of $X_2Y$ is __ kJ mol$^{-1}$ (nearest integer value).

Given: Bond energies of $X \equiv X$, $X = X$, $Y = Y$ and $X = Y$ are 940, 410, 500, and 602 kJ mol$^{-1}$ respectively.
valence $X$: 3, $Y$: 2

Answer
98